Solitary fibrous tumours (SFTs), also known as hemangiopericytomas, are a rare type of tumoura tissue mass that forms from groups of unhealthy cells that generally develops in mesenchymal or fibrous tissuea group of cells that work together to perform a function cellsthe basic structural and functional unit of all living things in the body. Mesenchymal tissue cells are those that help give organs shape and strength, and can develop into connective tissue, bloodthe red bodily fluid that transports oxygen and other nutrients around the body vessels and lymphatic tissue. Fibrous tissue cells are responsible for supporting, protecting, and holding bones, muscles, and other tissues and organs in place. Common examples of fibrous tissue include ligaments, tendonsa type of connective tissue that connects muscle to bone, the inner layer of the skin (hypodermis) and the sclera (the white, outer layer of the eye).
SFTs can be found anywhere in the body, and are generally benignnot cancerous, can grow but will not spread to other body parts. However, in rare cases SFTs can become malignantcancerous, may grow and spread to other areas of the body.
SFTs are generally diagnosed equally amongst the genders, and tend to be diagnosed between the ages of 50-70. However, anyone can develop this disease.
Types of Solitary Fibrous Tumours
There are several different types of SFTs, which are often categorised by the location the tumour develops in.
Pleuropulmonary Solitary Fibrous Tumours
Pleuropulmonary SFTs are one of the most common subtypes of SFTs, and tend to develop in the tissues of the lungs and pleuraa thin layer of tissue covering the lungs and the wall of the interior chest cavity. Most commonly, they develop in the middle to lower region of the chest in the visceral pleura (pleura lining the surface of the lungs), however they can also develop in the parietal pleura (thicker tissue that lines the inner surfaces of the thoracic cavity).
Pleuropulmonary SFTs are most commonly found in older individuals between the ages of 60-70, are often asymptomatic, and are often found while investigating another condition. In most cases, these tumours are benign, slow-growing, and can have a good prognosisto predict how a disease/condition may progress and what the outcome might be. However, in rare instances they may be malignant, aggressive, and may not have as good of a prognosis as benign pleuropulmonary SFTs.
Intraabdominal Solitary Fibrous Tumours
Intraabdominal SFTs are one of the most common subtypes of SFTs, and tend to develop within the abdomenstomach, stomach area, belly. The most common locations of intraabdominal SFTs are the peritoneumthe membrane that lines the abdominal cavity, retroperitoneuma space located behind the abdomen that contains many important bodily structures, such as the kidneys or pelvis, however it has also been found in the liver and genitourinary tract (including the bladdera hollow, muscular sac in the pelvis that stores urine, prostatea walnut-shaped gland in the male reproductive system that is responsible for producing semen - a bodily fluid that acts as a vessel for sperm transport during ejaculation, seminal vesicle and kidneya pair of bean-shaped organs in the abdomen that are responsible for filtering excess water and waste products from the blood and converting them into urine to be removed from the body).
Intraabdominal SFTs are often asymptomatic, and are generally found while investigating another condition. In most cases, these tumours are benign, slow-growing, and can have a good prognosis. However, in rare instances they may be malignant, aggressive, and may not have as good of a prognosis as benign intraabdominal SFTs.
Dural Solitary Fibrous Tumours
Dural SFTs are a rare subtype of SFTs that develop in the dura (the tough, outermost membrane of the brain and spinal cord) of the central nervous system (CNS). These tumours appear similar to meningiomas on imagingtests that create detailed images of areas inside the body scans, and are most commonly found between the ages of 47-56.
In most cases, dural SFTs are benign, slow-growing, and can have a good prognosis. However, in rare instances they may be malignant, aggressive, and may not have as good of a prognosis as benign dural SFTs.
Extracranial Solitary Fibrous Tumours of the Head and Neck Regions
Extracranial SFTs of the head and neck are a rare subtype of SFTs that develop in the regions of the head and neck not involving the brain. In most cases, these tumours develop in the sinonasal tract, the orbit (bony structure of the skull that holds the eye), or oral cavity.
Extracranial SFTs of the head and neck region are often asymptomatic, and are generally found while investigating another condition. In most cases, these tumours are benign, slow-growing, and can have a good prognosis. However, in rare instances they may be malignant, aggressive, and may not have as good of a prognosis as benign SFTs.
Soft Tissue Solitary Fibrous Tumours
Soft tissuetissue/the material that joins, holds up or surrounds inside body parts such as fat, muscle, ligaments and lining around joints SFTs are a rare subtype of SFTs that develop in deep soft tissue, most commonly in the limbs, abdominal wall, bones, and diaphragm. Unlike most other types of SFTs, these tumours are often detected earlier, and are often smaller when found.
Soft tissue SFTs are often asymptomatic, and are generally found while investigating another condition. In most cases, these tumours are benign, slow-growing, and can have a good prognosis. However, in rare instances they may be malignant, aggressive, and may not have as good of a prognosis as benign SFTs.
Solitary Fibrous Tumours of the Spinal Cord
SFTs of the spinal cord are a rare subtype of SFT that develops in the regions of the spinal cord other than the dura. These tumours are generally diagnosed earlier than other SFTs, often between the ages of 40 and 50.
Spinal cord SFTs are often asymptomatic, and are generally found while investigating another condition. In most cases, these tumours are benign, slow-growing, and can have a good prognosis. However, in rare instances they may be malignant, aggressive, and may not have as good of a prognosis as benign SFTs.
Treatment
If a SFT is detected, it will be staged and graded based on size, metastasiswhen the cancer has spread to other parts of the body, also known as mets, and how the cancera disease where abnormal cells split without control and spread to other nearby body tissue and/or organs cells look under the microscope. Stagingthe process of determining how big the cancer is, where it started and if it has spread to other areas and grading helps your doctors determine the best treatment for you.
In most cases, SFTs rarely need staging and grading as they are often benign, slow-growing or don’t have other high-risk features. If your SFT is malignant and does need staging and grading, it will be based on the location of your tumour.
Staging and Grading of SFTs in the Central Nervous System
SFTs of the CNS, including dural SFTs and spinal cord SFTs, are rarely staged as they rarely spread to other parts of the body. Instead, they are generally graded:
- Gradea description of how abnormal cancer cells and tissue look under a microscope when compared to healthy cells 1 (low grade) tumours: cancer cells present as slightly abnormal and are usually slow growing.
- Grade II (intermediate grade) tumours: cancer cells present as abnormal and grow faster than grade-I tumours.
- Grade III (high grade) tumours: cancer cells present as very abnormal and grow quickly.
Staging and Grading of SFTs outside of the Central Nervous System
SFTs outside of the CNS are generally staged and graded using the TNM staging system:
- T (tumour) indicates the size and depth of the tumour.
- N (nodea small lump or mass of tissue in your body) indicates whether the cancer has spread to nearby lymph nodessmall bean-shaped structures that filters harmful substances from lymph fluid.
- M (metastasis) indicates whether the cancer has spread to other parts of the body.
This system can also be used in combination with a numerical value, from stage 0-IV:
- Stage 0: this stage describes cancer cells in the place of origin (or ‘in situ’) that have not spread to nearby tissue.
- Stage I: cancer cells have begun to spread to nearby tissue. It is not deeply embedded into nearby tissue and had not spread to lymph nodes. This stage is also known as early-stage cancer.
- Stage II: cancer cells have grown deeper into nearby tissue. Lymph nodes may or may not be affected. This is also known as localisedaffecting only one area of body cancer.
- Stage III: the cancer has become larger and has grown deeper into nearby tissue. Lymph nodes are generally affected at this stage. This is also known as localised cancer.
- Stage IV: the cancer has spread to other tissues and organs in the body. This is also known as advancedat a late stage, far along or metastatic cancer.
Cancers can also be graded based on the rate of growth and how likely they are to spread:
- Grade I: cancer cells present as slightly abnormal and are usually slow growing. This is also known as a low-grade tumour.
- Grade II: cancer cells present as abnormal and grow faster than grade-I tumours. This is also known as an intermediate-grade tumour.
- Grade III: cancer cells present as very abnormal and grow quickly. This is also known as a high-grade tumour.
Treatment Options
Once your tumour has been staged and graded, your doctor may recommend genetic testinga procedure that analyses DNA to identify changes in genes, chromosomes and proteins, which can be used to analyse tumour DNA to help determine which treatment has the greatest chance of success, which analyses your tumour DNA and can help determine which treatment has the greatest chance of success. They will then discuss the most appropriate treatment option for you.
Treatment is dependent on several factors, including location, stage of disease and overall health.
Treatment options for SFTs may include:
- Surgerytreatment involving removal of cancerous tissue and/or tumours and a margin of healthy tissue around it to reduce recurrence to remove as much of the tumour as possible (dependent on location).
- Radiation therapya treatment that uses controlled doses of radiation to damage or kill cancer cells.
- Chemotherapya cancer treatment that uses drugs to kill or slow the growth of cancer cells, while minimising damage to healthy cells.
- Targeted therapymedication that targets specific molecular features of cancer cells.
- Clinical trialsresearch studies performed to test new treatments, tests or procedures and evaluate their effectiveness on various diseases.
- Palliative carea variety of practices and exercises used to provide pain relief and improve quality of life without curing the disease.
Risk factors
Because of how rare SFTs are, there has been limited research done into the riskthe possibility that something bad will happen factors of this disease.
Symptoms
The symptoms of a SFT will vary based on the location of the tumour.
Symptoms of Pleuropulmonary Solitary Fibrous Tumours
Symptoms of a pleuropulmonary SFT may include:
- Persistent cough.
- Dyspneadifficulty breathing, shortness of breath.
- Chest pain.
- Haemoptysiscoughing up blood.
- Inflammation of the lungs.
- Paraneoplastic syndromesa group of rare disorders that occur when the immune system has a reaction to a cancerous tumour within the body.
Symptoms of Intraabdominal Solitary Fibrous Tumours
Symptoms of an intraabdominal SFT may include:
- Abdominal massa growth of cells that come together to make a lump, may or may not be cancer.
- Abdominal pain.
- Unexplained weight loss/loss of appetite.
- Changes in urinary habits, potentially including:
- Dysuriaburning, tingling and/or stinging of the urethra when urinating.
- Urinary retention.
- Hydronephrosisa condition where one or both kidneys become swollen due to urine retention.
- Polyuriafrequent urination.
- Incontinenceloss of control over release of urine or faeces.
- Nauseato feel sick or likely to vomit and/or vomiting.
- Paraneoplastic syndromes.
- Constipationa condition where a person has difficulty passing faeces/stools.
Symptoms of Dural Solitary Fibrous Tumours
Symptoms of a dural SFT may include:
- Focal deficits.
- Seizures.
- Increased intracranial pressure (ICP), which carries its own set of symptoms:
- Blurred vision.
- Decreased alertness.
- Nausea and/or vomiting.
- Behavioural changes.
- Weakness/difficulties moving or talking.
- Fatiguea state of extreme tiredness or exhaustion, can be physical or mental.
- Confusion.
- Hypertensionhigh blood pressure.
- Shallow breathing.
- Headache.
- Paraneoplastic syndromes (a group of rare disorders that occur when the immune system has a reaction to a cancerous tumour within the body).
Symptoms of Extracranial Solitary Fibrous Tumours of the Head and Neck Regions
Symptoms of an extracranial SFT in the head and neck region may include:
- Mass on the eyelid.
- Excess tear production (if around the eye).
- Proptosisbulging or protrusion of one or both of the eyes out of the eye sockets, also known as exophthalmos.
- An obstruction of the sinus and/or nasal passages.
- Painless mass in affected area.
- Paraneoplastic syndromes.
Symptoms of Soft Tissue Solitary Fibrous Tumours
Symptoms of a soft tissue SFT may include:
- Painless mass in affected region.
- Nerve pain (if tumour grows onto a nerve).
- Paraneoplastic syndromes.
Symptoms of Solitary Fibrous Tumours in the Spinal Cord
Symptoms of an SFT in the spinal cord may include:
- Back pain.
- Radicular painpain that radiates from your back to other parts of the body, such as the legs and hips.
- Numbness, tingling, and/or weakness in the legs.
- Difficulty walking.
- Back pain that is worse at night.
Not everyone with the symptoms above will have cancer, but see your general practitioner (GP) if you are concerned.
Diagnosis
If your doctor suspects you have a SFT, they may order the following tests to confirm the diagnosisthe process of identifying a disease based on signs and symptoms, patient history and medical test results and refer you to a specialist for treatment:
- Physical examinationan examination of your current symptoms, affected area(s) and overall medical history.
- Imaging tests, potentially including:
- CT (computed tomography) scana type of medical imaging that uses x-rays and computer technology to create detailed images of the body.
- MRI (magnetic resonance imaging)a type of medical imaging that uses radiowaves, a strong magnet and computer technology to create detailed images of the body.
- Blood teststesting done to measure the levels of certain substances in the blood.
- Biopsyremoval of a section of tissue to analyse for cancer cells.